We propose to continue our studies on the basic organic chemistry of ozone and the relationship of that chemistry to environmental health with particular emphasis on mutagenesis and carcinogenesis. We will conduct physical organic studies on carbonyl oxides and dioxiranes in order to determine the electronic, steric, and stereochemical requirements for solution reactions of these two classes of organic peroxides. We will also carry out separate gas phase reactions of carbonyl oxides and dioxiranes with representative polycyclic aromatic hydrocarbons which have been absorbed on model particulate materials. The products of these reactions will be isolated by TLC, GPC and HPLC methods and then identified. In the case of dioxiranes, which are yellow-colored and hence subject to photolysis under ambient atmospheric conditions, some photochemical studies will also be carried out both in solution and the gas phase. The reactions requiring dioxiranes will take advantage of a newly discovered technique which permits preparation of solutions of pure dioxiranes. These combined studies will permit us to assess the separate potential for atmosphere activation of PAH by carbonyl oxides, dioxiranes, and ozone. This assessment in turn is related to the possible atmospheric formation of mutagens/carcinogens by these three chemical agents.